Safe and efficient swallowing is something that most people take for granted. However, a disruption to swallowing function (dysphagia) is not uncommon in the aging process and can have serious consequences for one's health (nutrition, hydration, pneumonia) and quality-of-life. Studies suggest that the prevalence of swallowing disorders in older individuals ranges from 15-74%, depending on the population sampled and/or the metric used to define dysphagia. Sarcopenia is the age-related loss of skeletal muscle mass, organization, and strength and is a widely-cited explanation for age-related decline in swallow function. Our recent research confirms that age-related muscle loss occurs in the pharynx (throat) alongside an associated increase in pharyngeal lumen (throat cavity) volume. It is unknown how this increase in pharyngeal volume impacts swallowing biomechanics and function. The long-term objective of this research is to establish a relationship between the extent of pharyngeal sarcopenia (represented by larger pharyngeal lumen volume) and swallowing impairment. The central hypothesis of this proposal is that greater pharyngeal lumen volume will be associated with impaired swallowing biomechanics (pharyngeal constriction and shortening) and function (post-swallow residue). A novel application of Acoustic Reflection Technology (ART) will provide the innovative method to non-invasively measure pharyngeal lumen volume. Adopted from sleep science and dental research, ART functions similar to sonar. Sound waves are introduced into the mouth and throat and are reflected back to a microphone. Based on the acoustic reflection, a representation of the pharyngeal lumen can be calculated. ART measures of pharyngeal volume will be compared with biomechanical and functional measures of swallowing using a standardized videofluoroscopy (VF) protocol. This same VF protocol will also yield the data to establish the efficacy of a pharyngeal maneuver, called the Effortful Swallow (ES), to improve swallowing biomechanics and function. We expect to find that the ES improves measures of pharyngeal constriction, pharyngeal shortening and residue compared with regular swallows from the same individual. This data will provide the foundation for a future exercise-based intervention/prevention study using the ES to combat pharyngeal muscle loss. The proposed research is significant and timely. As the mean age of our population rapidly shifts upwards, it is critical to understand how, when and why natural aging of the swallowing mechanism transforms into a swallowing disorder. It is anticipated that this work will establish the following; (1) an inverse relationship between pharyngeal lumen volume and swallowing biomechanics and function, (2) the utility of the ES to improve swallowing biomechanics and function and (3) the value of ART to monitor age- related change in the pharynx. Together this will inform a future program of research on the prevention/rehabilitation of pharyngeal sarcopenia.